I've noticed on a couple of long trips that Waze does not pick the fastest or shortest route by default when I choose my destination.

For example, last night I started Waze and set my destination as my home location. The window immediately popped up showing a route of 284 miles that would take 4h 22min. I knew this wasn't correct, so I selected the routes button to generate alternate routes. In my alternate route list, there were two other routes that were both shorter and faster. My preferences are set to take the fastest route and I do not have the avoid highway option selected.

Here are the routes that were shown:

waze_routs.PNG (100.3 KiB) Viewed 4763 times

Just as a test, I left it on the route it selected by default and continued to drive on the route that I knew was the fastest so I could see how long it would take before it recalculated to the best route. Once I was about 10 miles into the route and it had suggested numerous u-turns, it finally picked the correct route and shaved 30 minutes and 30+ miles off of the trip.

Is there another preference that dictates which route it should pick by default? I've never driven the route it suggests since it is often heavily congested with traffic which makes it even slower. In this case, I know the route so it's not such a big deal since I'm only running Waze for traffic and road updates. But in an unfamiliar area, this doesn't give me much confidence that I'm getting the proper route without digging through all the alternate routes first.

I had previously found some missed segments in my desired route that were preventing Waze from routing on it correctly. Before I made those corrections, Waze wouldn't even find the route when looking for alternates. The roads in the route are all intact now since it will find my route in the alternates now.

I've considered the "highway and above" rule as a possibility, but my desired route is primarily Highway and Freeway, except for the endpoints and one short section in the middle where I connect from the Major Highway to the Freeway on a Minor Highway and a Service Road/Ramp. That transition is about a mile of mostly service road parallel to the interstate to pick up the next entry ramp. The only real difference I can see is that the route that Waze is picking contains more Freeway and less Major Highway (about 45 miles of Major Highway and 220 miles of Freeway). The route I follow that is faster is more of a mix with around 100 miles of Major Highway and 130 miles of Freeway.

The other odd part is that on the reverse direction of the trip shown, it will always pick the same routing that it picked here, but my desired route won't usually display as an alternate. However, once I get closer to the point where I can exit the freeway to take the highway, it will change the route to save time and use the highway. Doesn't doesn't appear to be related to any missing map edits since the re-route occurs while I'm still on the interstate many miles north of the intersection.

Last edited by AggieJM on Wed Dec 12, 2012 3:27 pm, edited 1 time in total.

The purple route displayed is the default route that Waze gives me that is longer.

My desired route is actually a hybrid of the blue and purple routes. I follow the blue route from Giddings up to Waco where it merges with the purple route.

From there, I follow the purple route to my destination north of Dallas. The last part of the blue route through Fort Worth is hit or miss on traffic and construction at time.

If you want to see the actual route I follow in Waco, the following screenshot shows the turn I take. I make a left from Robinson Dr/US Hwy 77 onto Garden Dr/New Rd (shown by the red arrow) to get over to I-35. This allows me to miss the traffic circle further north on Robinson Dr. I don't expect Waze to necessarily route this path since Garden Dr/New Rd is only marked as Primary Street, but it is faster than taking the traffic circle.

This screenshot doesn't tell me anything as I'm not aware of the US highways, but let me give you my ¢2 as a potentially similar case is happening here in Portugal.

I've read and noticed myself that for long routes (in practice >10KM, surely >20KM) waze only uses highway or above to calculate the routes. Here in Portugal we basically have freeways, national and regional roads, and the default for a while was to not use minor or major highways even for the national roads, because and I quote "a regular road with one lane each way, with potholes and not much wider than a car can't be a highway", so what happens now is that some national roads are already minor or major, but others aren't. To keep it simple, waze will try hard to follow the highways even if it means going around a national road still marked as primary or something.

This is confusing for the general users as they will wonder why waze selects a longer drive when both are the same kind of road, so we're trying hard to fix up all those main grid roads all over the country.

Another reason may be a lost red segment in a locked freeway. We had some of those cases, where the route goes along the freeway, then decides to leave the freeway to go around the red arrow, and then goes back in.

In conclusion, first try to check if the routes you are expecting and the ones waze suggests are correctly edited. Then if everything is correct, there may still be other reasons for the incorrect selection. I myself have a route that is not picked by default even though is the one I drive everyday and the shortest and fastest one, and the segments are all 100% correct. Then the client learns it and starts picking it up. Then a mapdate happens, the cache is cleared, and it gives me the wrong one again.

AggieJM wrote:(...)Also I've considered the "highway and above" rule as a possibility, but my desired route is primarily Highway and Freeway, except for the endpoints and one short section in the middle where I connect from the Major Highway to the Freeway on a Minor Highway and a Service Road/Ramp. (...)

I never got hold of what a Service Road really is meant to, but I see a lot of "behaves like Primary" and that segment in the middle may affect your route, maybe?

Can you post a link from livemap with the route? I'm now really curious

I'd then add something else I've read somewhere but I'm not sure now of details, but it's something I'm trying to investigate because it affects a case of mine similar to this one. And I might be just wrong with these assumptions, but hopefully someone will correct me (hint hint).

I've read that the information about traffic congestion (speed average, user reports, etc) is not considered for the whole drive (these long ones), but only for the next miles at the time, meaning that when you leave, the backend will see two routes, indeed one shorter and faster than the other taking in consideration the overall averages of all segments involved, but the calculation with the current average and reports is only taken from the first dozen of miles, so even if the blue is overall shorter, probably the first miles are slower than the pink one and hence why it picks one that overall may be worse, but in the beginning is better. You tell me from your experience. Then as you drive, the backend grabs the current information from the next dozen miles and as I recall, unfortunately will only try to re-route if the information is really bad, whatever that means.

This kind of makes sense because it probably doesn't make sense to take in consideration an accident or slow traffic 200 miles away or 2 or 3 hours away for calculating the route, as it may clear up in the meantime - or get even worse.

I'd suggest next time you try to route to some point in the middle where the two lines intercept, and see if that half of the route picks the route you'd like. Then when you reach that point, do a new navigation (or just pick alternatives) and see again which route it will pick by default. This way you can try to split the calculation of both halfs and try to identify which one is being overriden by the current traffic vs. the overall speed/length.

WeeeZer14 wrote:A Service Road is considered a local street and it is treated the same as Street or Primary Street. Therefore it will be heavily penalized or flat out ignored for long trips.

I've mentioned it because I see on the forums that a primary is a local street, as you call it, but there is a page on the wiki that mentions primaries as potential candidates for long routes. I'm personally assuming the wiki is wrong. I'm mobile now so I don't have the link here

WeeeZer14 wrote:Well it just gets muddy in that it depends on how long a trip is before it is pruned. So at some distance all roads are used, then streets drop out, then later primary drops out, and so on. At least that seems to be how it works, we of course can't know every trade secret they use in the routing engine

Sometimes we've heard support say that Primary is the same as Street. Other times that it is different and will be used on longer trips. But I am pretty sure that I only recall Service Road being compared to Street. A Service Road is used to get to a specific business or residence. It isn't used to pass through on your way to somewhere else.

We're getting out of topic, but for completeness the rule I read is that "the first 10KM and the last 10KM uses any kind of road, and the distance in between uses only highway or above". On first read one would assume that a route with up to 20 KM would use any kind of street. It doesn't in my experience. Anything above 10KM will demand a highway even if there is a straight line with streets/primaries. Only if no route at all exist with highways, it will then fall back to the 10+10. Then maybe above those 20KM, but certainly above 100KM, it just gives up. This has been my experience.

The Service Road I still don't understand it, so I'm trying to avoid it. It surely doesn't behave like a private or parking road as I did the mistake of using service road for the gas station and now I'm getting routes going through it, so it does look like behaving like a street or primary. So my experience is contrary to the "isn't used to pass through". But on the other hand I've seen waze "using to pass through" boardwalks and walking trails, so I'd rather use what I know and ensure those non drivable ones are not even connected at all

WeeeZer14 wrote:A Service Road is considered a local street and it is treated the same as Street or Primary Street. Therefore it will be heavily penalized or flat out ignored for long trips.

I've mentioned it because I see on the forums that a primary is a local street, as you call it, but there is a page on the wiki that mentions primaries as potential candidates for long routes. I'm personally assuming the wiki is wrong.

Well it just gets muddy in that it depends on how long a trip is before it is pruned. So at some distance all roads are used, then streets drop out, then later primary drops out, and so on. At least that seems to be how it works, we of course can't know every trade secret they use in the routing engine

Sometimes we've heard support say that Primary is the same as Street. Other times that it is different and will be used on longer trips. But I am pretty sure that I only recall Service Road being compared to Street. A Service Road is used to get to a specific business or residence. It isn't used to pass through on your way to somewhere else.